The overall objective of the research portion of this proposal will be to correlate the specificity of naturally occurring salivary antibodies against purified Streptococcus mutans cell wall and surface antigens with resultant caries or caries immunity in humans. Two broad populations of subjects will be employed in these studies; normal healthy and IgA deficient (including patients compensating with other immunoglobulin isotypes in their saliva) subjects. These populations will be further divided into caries-resistant and caries-prone groups based on examination and historical record. Using an enzyme-linked immunosorbent assay (ELISA), parotid saliva and serum will be assessed for the level, specificity and isotype of antibodies to the following cell wall and cell surface antigens: glucosyltransferase, surface antigens I/II and III, 1-3 and 1-6 linked dextrans, peptidoglycan, lipoteichoic acid, and serotype carbohydrates and cell walls from serotypes a - g. In addition, the antibody levels and specificities of IgA1 and IgA2 subclasses against these antigens will be measured by radioimmunoassay. The IgA deficient subjects lacking salivary anti-S. mutans antibodies will be used to substantiate the importance of this immune system in caries immunity. In those IgA deficient patients exhibiting compensating salivary IgM (and IgG) antibodies, measurements will be made using ELISA as to the level and specificity of these compensating antibodies against S. mutans surface antigens and compared with their caries experience. It is anticipated that the results of these studies will demonstrate the role of salivary IgA antibodies in protection against dental caries and will also demonstrate the specificity of antibodies of importance in defense against this oral disease. In addition to the research component of this program, a plan is formulated, by which the applicant for the Dentist Scientist Award can increase his skills and knowledge in the dental treatment of the medically, physically and mentally compromised patients. The didactic, clinical and research components outlined in this proposal have been carefully prepared to allow maximum development of Dr. Filler as a Clinical Investigator.